Results from Prototype Advanced LIGO Seismic Isolation

In 2008, new seismic isolation systems were installed in the two LIGO 4km gravitational wave detectors. These systems are prototypes of the system planned for Advanced LIGO which will achieve improved interferometer sensitivity to astrophysical events. We present the measured performance of the new isolation systems. We compare this to the current advanced LIGO requirements and discuss potential improvements which may allow even better performance in the future.